Wednesday, September 21, 2011

Generating Power Through Vibrations!

Generating power through footsteps and similar high frequency processes are not a new concept today. Scientists and researchers have generated electricity through vibrating machines, surfaces etc. However such surfaces and objects are limited. Moreover, a constant problem faced by such sources is that the electricity so generated is not constant. It is hence essential to develop ways so as to conserve this otherwise wasted energy. Scientists from MIT have constructed a small device which can generate electricity from vibrations which have a very low frequency associated with them.


Energy Harvester

 A new energy harvesting device converts low-frequency  vibrations into electricity.


The device is so designed that it can pick up vibrations even from physical system like pipes and bridges. The gadget is constructed is called a microelectromechanical system (MEMS). The device is capable of producing 100 times more energy than what is generated by devices that operate with higher frequency signals.

For harnessing such low frequency vibrations we have materials like piezoelectric crystals like Quartz. This can be done by planting piezoelectric material on the top of a cantilever beam. When the beam is subjected to vibrations the piezoelectric materials is stretched and compressed. This makes it easier for us to convert mechanical energy into electrical energy.

Presently all of the things which are mentioned above are quite costly and it is not possible if we want to have a stable electric source by having more number of such cantilever beams. The researchers have hence tried to find out a new way to answer this difficulty. Instead of taking up the conventional cantilever beam approach, they have instead designed a microchip using the piezoelectric material and anchored it on both the ends of chip. Later on, the researchers added a small weight in the middle of chip and then subjected them to a series of vibrations. In this experiment it was observed that it is not only a specific frequencies but the arrangement responded to a large number of frequencies.

This maximizes our chance to produce electricity at any rate that vibrations are produced. The researchers have been able to generate 45 micro watts of power through the improved design. They now want to take it to a higher ‘power level’ and generate 100 micro watts. This will be a major breakthrough in the power generation segment because no one had ever produced that much of power through a single PZT (piezoelectric material) layer. The power produced sometime in future will thus be a clean power.

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